ON THE APPROXIMATE APPLICABILITY OF THE SCHRODINGER EQUATION TO NON- ISOLATED SYSTEMS
B. Sredniawa, J. Weyssenhoff · Acta Phys. Polon. · 1963
Problems in which Schrodinger's equation with timedependent hamiltonian is applied to one system should rather be considered as representing cases of two systems, the second acting appreciably on the first but not inversely; the systems as a whole is then considered to be isolated and, consequently, subject to treatment by means of a Schrodinger equation with time-independent hamiltonian. The composition and decomposition of systems is dealt with by the method of statistical operators of v. Neumann. Both methods of dealing with the problem are shown to lead in good approximation to the same results, but only for times fulfilling a given inequality. (auth)